Conventional methods of water removal includes a reciprocating down-hole pump actuated by rods from a working head mounted at the well head. Gas flows from the well cap, and water is pumped out of the well at regular intervals of time, i.e. on a time cycle. The pump may operate for a period of time and be stopped for a second period of time. The pump would be damaged if no water was present. Accordingly, the operating and shut down times of the pump must be so calculated as to permit water to rise to a predetermined level (usually estimated) before the pump is operated to lower the water to an acceptable, estimated level.
Accurate water levels are rarely known and often the well will be pumped to a level where no water enters the pump, resulting in damage to the latter. In order to prevent such damage, the time cycle is so chosen as to ensure that there is water in the pump at all times during operation thereof. During the time when the pump is not operating, water rises in the casing, covering the perforations and creating a back pressure, which reduces gas production. With such a hit-and-miss method, there is a distinct possibility of damage to the pumping unit, in which case it is necessary to remove the rods and pump and repair and re-install the unit. No gas is produced while repairs are being made. In an effort to reduce the possibility of pump failure due to a lack of water, a water level differential in the well may be as much as 100 feet, say from 20 feet above the pump to 120 feet above the pump, consequently, gas production is reduced by an average of 70 feet head of water, or 30 p.s.i. back pressure on the perforations.
The initial cost of the equipment described above may be as high as $30,000.00. In the case of low production wells, an investment of this magnitude added to repair costs may make it uneconomical to produce gas and the well is shut-in (closed).
At present, there are many wells which have been "shut-in" for this reason.
Thus, it is readily apparent that there is a need for an efficient system for the removal of water from a gas producing well. One system for removing water from a gas well is disclosed by U.S. Pat. No. 2,061,865, which issued to W. T. Wells on Nov. 24, 1936. The system proposed by Wells relies on a compressor for forcing air into the well when a pressure gauge at the surface indicates a reduction in flow pressure due to the ingress of water into the well. The air is driven under pressure through a Venturi located at the bottom end of tubing mounted in the casing for drawing water out of the well casing. The gauge must be monitored and incorporated into an automated valve system with the electrical and pneumatic controls necessary to operate the apparatus, i.e. to start the engine or motor for driving the compressor in response to the reduced gas pressure. Because the system is switched on and off in accordance with the ingress of water into the well, i.e. operation is intermittent, gas production cannot be at a maximum. Moreover, the Wells system relies on a complicated packer with built-in check valves for controlling air and/or water or gas flow.
Thus, there still exists a need for a simple system for the efficient removal of water from a gas producing well.